1. Field of the Invention
The invention in general relates to information transfer from one device to another, and more particularly to an improved radio frequency (RF) arrangement for accomplishing the transfer.
2. Description of Related Art
Various systems exist wherein information is to be transferred from one location to another such as in remote monitoring, data collection, computer-to-computer information exchange, parcel tracking and delivery systems, to name a few.
In order to eliminate the need for a hardwire connection between devices of the system, use is made of an optical coupling or an RF modem to transmit and/or receive such information, thus providing a high degree of portability, within a given range.
Optical coupling arrangements require an unobstructed optical transmission path or, for a more positive transfer, a physical coupling of a device with a docking mechanism.
RF modems are widely used to eliminate the problems associated with hardwired or optical arrangements. For many applications existing RF modems may be too large to be incorporated into a relatively small host device. In addition, these RF modems are expensive and require relatively frequent battery charges.
The present invention provides an RF modem which can be used for secure and reliable information transfer and which RF modem is relatively small and inexpensive, with reduced power consumption.
An RF modem coupled to a host device is provided for transmitting RF information signals to, and receiving RF information signals from, another RF modem coupled to a host device, in an array of host devices. The modem preferably utilizes a superregenerative circuit for transmission and reception of information encoded in a binary format and transmitted by Manchester encoded On/Off keying. Recovery of information is accomplished by obtaining time indications of oscillator waveform buildup to a certain level in the superregenerative circuit. The modem is operable in an active mode of operation as well as a power saving idle mode which is comprised of a sleep mode of operation, in which no scanning for the presence of RF signals is performed, and a power saving scanning mode of operation in which the modem scans for the presence of RF signals.